# CVE-2026-34219: libp2p rust-libp2p denial of service in Gossipsub heartbeat

Source: https://junglewise.ai/threats/cve-2026-34219-libp2p-rust-libp2p-denial-of-service-in-gossipsub-heartbeat  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-31. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-34219 · Severity: medium · CVSS 5.9 · Published 2026-03-31

A vulnerability in the Rust implementation of the libp2p networking stack allows a remote attacker to crash a target node. By sending a specially crafted message, an attacker can trigger a system failure (panic) during the software's internal heartbeat process. This results in a denial-of-service, potentially disrupting decentralized applications or blockchain nodes that rely on this networking library.

Vendors: [crates.io](https://junglewise.ai/threats/vendors/crates-io), [Libp2p](https://junglewise.ai/threats/vendors/libp2p).

## Quick answers

**Is CVE-2026-34219 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34219 being exploited in the wild.

**How severe is CVE-2026-34219?** Medium severity, with a CVSS score of 5.9, published 31 March 2026.

**Which products and versions are affected?** libp2p-gossipsub (crates.io) SEMVER:introduced=0,fixed=0.49.4; Libp2p Rust-Libp2p-Gossipsub < 0.49.4.

**Is there a fix for CVE-2026-34219?** Yes. libp2p-gossipsub (crates.io): upgrade to 0.49.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-34219 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-34219?** Check whether you run libp2p-gossipsub (crates.io) or Libp2p Rust-Libp2p-Gossipsub at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- libp2p-gossipsub (crates.io): upgrade to 0.49.4 or later

  ```sh
  cargo update -p libp2p-gossipsub
  ```


## Technical details

The vulnerability exists in the Gossipsub implementation of rust-libp2p due to unchecked arithmetic in the heartbeat expiry logic. An attacker can send a crafted PRUNE control message containing a near-maximum backoff value. While the initial storage of this value uses checked addition, a subsequent heartbeat process performs unchecked 'Instant + Duration' arithmetic (backoff_time + slack). This causes an integer overflow and a process panic. The issue is reachable by any unauthenticated peer over standard TCP + Noise connectivity and has been patched in version 0.49.4.

## Affected products

- libp2p rust-libp2p-gossipsub < 0.49.4

## Identifiers

- CVE-2026-34219
- GHSA-xqmp-fxgv-xvq5

## Timeline

- 2026-03-27: advisory: GitHub Security Advisory published
- 2026-03-31: disclosed: CVE published to NVD

## References

- [https://github.com/libp2p/rust-libp2p/security/advisories/GHSA-xqmp-fxgv-xvq5](https://github.com/libp2p/rust-libp2p/security/advisories/GHSA-xqmp-fxgv-xvq5)

## Related threats

- [Gossipsub PRUNE.backoff Duration Overflow](https://junglewise.ai/threats/cve-2026-33040-gossipsub-prune-backoff-duration-overflow)